The invention relates to a coupling assembly for a transmission assembly, in particular for a multiple spider planetary gear mechanism, the transmission assembly having two speed-change gear mechanisms which are coupled to one another. Furthermore, the invention relates to a transmission assembly, in particular for a drive device of a vehicle, in particular for a vehicle having an electric motor, having an input shaft, an output shaft, two speed-change gear mechanisms which are coupled to one another and a coupling assembly.
Transmission assemblies having a plurality of speed-change gear mechanisms are known from the prior art. A plurality of transmission ratios can be switched by way of corresponding coupling of the speed-change gear mechanisms among one another. For example, planetary gear mechanisms which are coupled to one another are used as speed-change gear mechanisms, it being possible for individual elements of one or both planetary gear mechanisms to be braked or blocked by way of shifting elements, for example brakes or clutches. Here, as is also the case in other transmissions, shifting of the individual gears without load interruption is possible if a suitable clutch is used.
For example, a multiple spider planetary gear mechanism is known, in which the sun gear of a first planetary gear mechanism is coupled to an input shaft, and the spider which supports the planetary gears is coupled to an output shaft. The spiders of both planetary gear mechanisms are coupled in each case to the internal gear of the other planetary gear mechanism. A first shifting element can block the spider of the second planetary gear mechanism, and a second shifting element can block the sun gear of the second planetary gear mechanism.
If the first shifting element is actuated, the spider of the second planetary gear mechanism and therefore that internal gear of the first planetary gear mechanism which is coupled to it are blocked. The power flow takes place directly from the sun gear of the first planetary gear mechanism via its planetary gears and the spider to the output shaft.
In contrast, only the sun gear of the second planetary gear mechanism is blocked by way of blocking of the second shifting element. All other components can move, with the result that the power flow takes place via both planetary gear mechanisms, as a result of which a second gear is realized. However, an increase in the number of gears is possible only by way of a plurality of planetary gear mechanisms, as a result of which a greater amount of installation space is required.
In the case of the transmission assemblies which are known from the prior art, generally either the number of gears is very limited, or a large number of shifting elements and/or speed-change gear mechanisms are required, in order to select the individual gears. As a result, the construction and the control of the transmission assemblies are very complicated.
It is an object of the invention to provide a coupling assembly for a transmission assembly of this type, which coupling assembly has a simpler construction and makes the selecting of a plurality of gears possible. Furthermore, it is an object of the invention to provide a transmission assembly which has a simpler construction and by way of which as large a number of gears as possible can be selected with a small number of shifting elements.
In order to achieve the object, a coupling assembly for a transmission assembly is provided, in particular for a multiple spider planetary gear mechanism. The transmission assembly has two speed-change gear mechanisms which are coupled to one another, a first shaft and a second shaft which can be coupled to one of the speed-change gear mechanisms and a third shaft. It is possible for two shift stages of the transmission assembly to be shifted by way of the blocking of, in each case, one of the first and second shafts. A first shifting element and a second shifting element are provided which, in each case, couple the first shaft and the second shaft to the third shaft, and a third shifting element is provided which can brake and/or block the third shaft.
By way of the coupling assembly according to the invention, shifting of a total of three gears is possible in the case of two speed-change gear mechanisms with three shifting elements. In the case of a blocked third shifting element, two gears can be realized by way of shifting of the first and the second shifting element. A third gear can be provided by both the first and the second shifting element being shifted while the third shaft is released by way of the third shifting element. In this shifting position, the first and the second shaft are coupled to one another, with the result that a third gear, that is to say a third transmission ratio, is produced by way of the coupling of the speed-change gear mechanisms which are connected to the shafts.
The first, the second and/or the third shifting element can be formed in each case by a brake which blocks the respective shaft, that is to say arrests it completely.
The first, the second and/or the third shifting element can also be formed, however, in each case by a clutch, with the result that slow coupling or blocking of the respective shafts and therefore a gentle transition between the transmission ratios, that is to say the individual gear stages, are possible.
The clutches are preferably configured as a multiple disk clutch, by way of which a satisfactory transmission of power with a low installation space is possible.
In order to ensure a loss-free drive, a bearing is preferably provided for the first, the second and the third shaft, with the result that these shafts can rotate with minimal friction.
In order to achieve the object, furthermore, a transmission assembly, in particular for a drive device of a vehicle, in particular for a vehicle having an electric motor, is provided, having an input shaft, an output shaft and two speed-change gear mechanisms which are coupled to one another, and having a coupling assembly according to the invention. The first and the second shaft are coupled to the first and/or the second speed-change gear mechanism, and it is possible for three transmission ratios between the input shaft and the output shaft to be selected by way of selective shifting of the three shifting elements.
The speed-change gear mechanisms are, for example, planetary gear mechanisms which in each case have a sun gear, a plurality of planetary gear mechanisms which are mounted on a spider, and an internal gear. The planetary gear mechanisms make a very compact construction of the transmission assembly possible. Shifting of the gears without load interruption is possible.
In the case of a transmission assembly of this type, the spider of the first speed-change gear mechanism is preferably coupled to the internal gear of the second speed-change gear mechanism, and the spider of the second speed-change gear mechanism is coupled to the internal gear of the first speed-change gear mechanism. Depending on the shifting and/or arrangement of the shifting elements, merely the first planetary gear mechanism can be utilized for speed changing, or the load path passes from the first planetary gear mechanism via the second planetary gear mechanism.
In one preferred embodiment, the first shaft of the coupling assembly is coupled to the spider of the second speed-change gear mechanism, and the second shaft of the coupling assembly is coupled to the sun gear of the second speed-change gear mechanism. In the case of a blocked third shaft, a first gear can be shifted by the first shifting element blocking the spider of the second speed-change gear mechanism and therefore the internal gear of the first speed-change gear mechanism. The power flow takes place directly from the sun gear of the first planetary gear mechanism via its planetary gear mechanism and the spider to an output shaft. If the second shaft is blocked by the second shifting element, merely the sun gear of the second speed-change gear mechanism is arrested, with the result that the power flow takes place via both planetary gear mechanisms. A third gear is shifted by the third shaft being released, that is to say the third shifting element being opened, while the first and the second shifting element are closed. As a result, the first shaft is coupled to the second shaft, the planetary gear mechanisms being blocked by way of the coupling action, with the result that both planetary gear mechanisms rotate together and a third gear is shifted.
The input shaft is preferably coupled to the sun gear of the first speed-change gear mechanism, and the output shaft is coupled to the spider of the first speed-change gear mechanism.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.